A variety of metallocenes and other single site-like catalysts have been developed to prepare olefin polymers. Metallocenes are organometallic coordination complexes containing one or more .pi.-bonded moieties (i.e., cyclopentadienyl groups) in association with a metal atom. Catalyst compositions containing metallocenes and other single site-like catalysts are highly useful in the preparation of polyolefins, producing relatively homogeneous copolymers at excellent polymerization rates while allowing one to tailor closely the final properties of the polymer as desired.
Recently, work relating to certain nitrogen-containing, single site-like catalyst precursors has been published. PCT Application No. WO 96/23101 relates to di(imine) metal complexes that are transition metal complexes of bidentate ligands selected from the group consisting of: ##STR2## wherein said transition metal is selected from the group consisting of Ti, Zr, Sc, V, Cr, a rare earth metal, Fe, Co, Ni, and Pd;
R.sup.2 and R.sup.5 are each independently hydrocarbyl or substituted hydrocarbyl, provided that the carbon atom bound to the imino nitrogen atom has at least two carbon atoms bound to it; PA1 R.sup.3 and R.sup.4 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl, or R.sup.3 and R.sup.4 taken together are hydrocarbylene or substituted hydrocarbylene to form a carbocyclic ring; PA1 R.sup.44 is hydrocarbyl or substituted hydrocarbyl, and R.sup.28 is hydrogen, hydrocarbyl or substituted hydrocarbyl or R.sup.44 and R.sup.28 taken together form a ring; PA1 R.sup.45 is hydrocarbyl or substituted hydrocarbyl, and R.sup.29 is hydrogen, substituted hydrocarbyl or hydrocarbyl, or R.sup.45 and R.sup.29 taken together form a ring; PA1 each R.sup.30 is independently hydrogen, substituted hydrocarbyl or hydrocarbyl, or two of R.sup.30 taken together form a ring; PA1 each R.sup.31 is independently hydrogen, hydrocarbyl or substituted hydrocarbyl; PA1 R.sup.46 and R.sup.47 are each independently hydrocarbyl or substituted hydrocarbyl, provided that the carbon atom bound to the imino nitrogen atom has at least two carbon atoms bound to it; PA1 R.sup.48 and R.sup.49 are each independently hydrogen, hydrocarbyl, or substituted hydrocarbyl; PA1 R.sup.20 and R.sup.23 are independently hydrocarbyl or substituted hydrocarbyl; PA1 R.sup.21 and R.sup.22 are independently hydrogen, hydrocarbyl or substituted hydrocarbyl; and PA1 n is 2 or 3; PA1 and provided that: PA1 X and Y are each heteroatoms; PA1 each Cyclo is a cyclic moiety; PA1 each R.sup.1 is a group containing 1 to 50 atoms selected from the group consisting of hydrogen and Group IIIA to Group VIIA elements, and two or more adjacent R.sup.1 groups may be joined to form a cyclic moiety; PA1 each R.sup.2 is a group containing 1 to 50 atoms selected from the group consisting of hydrogen and Group IIIA to Group VIIA elements, and two or more adjacent R.sup.2 groups may be joined to form a cyclic moiety; PA1 W is a bridging group; and PA1 each m is independently an integer from 0 to 5. PA1 X and Y are each heteroatoms; PA1 each Cyclo is a cyclic moiety; PA1 each R.sup.1 is a group containing 1 to 50 atoms selected from the group consisting of hydrogen and Group IIIA to Group VIIA elements, and two or more adjacent R.sup.1 groups may be joined to form a cyclic moiety; PA1 each R.sup.2 is a group containing 1 to 50 atoms selected from the group consisting of hydrogen and Group IIIA to Group VIIA elements and two or more adjacent R.sup.2 groups may be joined to form a cyclic moiety; PA1 W is a bridging group; and PA1 each m is independently an integer from 0 to 5; PA1 each R.sup.1 is a group containing 1 to 50 atoms selected from the group consisting of hydrogen and Group IIIA to Group VIIA elements and two or more adjacent R.sup.1 groups may be joined to form a cyclic moiety; PA1 each R.sup.2 is a group containing 1 to 50 atoms selected from the group consisting of hydrogen and Group IIIA to Group VIIA elements and two or more adjacent R.sup.2 groups may be joined to form a cyclic moiety; PA1 W is a bridging group; and PA1 each m is independently an integer from 0 to 5;
said transition metal also has bonded to it a ligand that may be displaced by or added to the olefin monomer being polymerized; and PA2 when the transition metal is Pd, said bidentate ligand is (V), (VII) or (VIII).
An olefin polymerization catalyst composition is described herein having good polymerization activity and productivity. The catalyst composition comprises a heteroatom-containing catalyst precursor having the formula: ##STR3## wherein M is a Group IVB metal; each L is a monovalent, bivalent, or trivalent anion;
The catalyst precursor may be conveniently prepared by reacting a Group IVB organometal compound with a heteroatom-containing ligand of the formula: ##STR4## wherein X, Y, W, Cyclo, R.sup.1, R.sup.2, and m have the meanings stated above.